Sewing-machine mechanism for performing darning operations



Dec. 20, 1949 sc -r 2,491,622

SEWING MACHINE MECHANISM FOR PERFORMING DARNING OPERATIONS Filed June 14, 1948 I N I 'EN TOR.

Bernard/4. 50/207132? BY Patented Dec. 20, 1949 SEWING-MACHINE MECHANISMFOR PERI- FORMING DARNING' OPERATIONS Bernard A. Schmitt, Chicago, 111.

Application June 14, 1948, Serial No. 32,767

My invention relates to sewing machine mechanisms for performing darning operations.

The principal object of; this invention is to provide a simple and inexpensive arrangement whereby the sewing machine may by a simple adjustment be converted for d-arning purposes.

Ancillary to this object is the provision for accomplishing the same by an arrangement; which requires the minimum modification of a standard sewing machine head and pressure foot.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanyin drawings showing the preferred form of construction, and in which:

Fig. 1 is a fragmentary part sectional detail view of a sewing machine head with which my invention is associated;

Fig. 2 is a fragmentary perspective view of the sewing machine head and base showing the same converted for darning operation;

Fig. 3 is a fragmentary sectional detail view taken substantially on line 33 of Fig. 1;

Fig. 4 is a perspective view of one of the springs embodied in the invention; and

Fig. 5 is a plan view of a specimen of decorative work which may be accomplished by my invention.

In order to appeal to the operator of a sewing machine, who generally i not mechanically inclined but who has been taught how to operate a sewing machine efficiently, it is most desirable that the parts of the sewing machine which must be adjusted by this operator require the minimum degree of elfort and skill on his or her part.

With this in mind, I have provided an arrangement whereby by a simple adjustment, the sewing machine may be conditioned for darning purposes. This arrangement will now be described and explained.

In the drawings, wherein I have illustrated the preferred form of construction of my invention,

the sewing machine comprises the usual hollow head I0 and base I I. This head includes the cover plate Ill removably secured thereto by the usual screws ll. Associated with this head It is the needle bar i2 and pressure bar l3. The pressure bar I3 carries the pressure foot l4 which cooperates in the usual and well-known manner with the feed dogs (not shown) of the sewing machine for feeding the cloth being sewed. In carrying out the objects of my invention, I form in the head [0 a threaded bore l5. In this bore 1 Claim. (Cl. 112-236) a nut it. This nut 16 has a-knurled head I! to facilitate threading the nut lfi into the threaded bore i5. This-nut it is preferabl hollow and receives the upper end portion it Of the pressure bar it.

Formed in the head it is an elongated slot l9. Projecting into this slot l9 is'a guide finger 28. This guide finger it provides a split sleeve 2| which embraces the pressure bar l3. This guide finger 2G is adapted to be engaged by the cam head 22 of a lifting lever 23 pivoted to the head as at 24 and operating in the lower end portion of the slot it. This cam head 22 is adapted to engage the finger it when pivoted in a clockwise direction as viewed in Fig. 1, to move the pressure bar it upwardly to relieve the pressure of the foot M upon the goods 25. This operation of the lifting lever 23 is well-known in the art of sewing machines.

Embracing the pressure bar 13 and arranged between the not it and the sleeve 2i is a sprin 26. The parts providing this sleeve 2! are secured together by suitable nut and bolt 21.

Embracing the pressure bar l3 and arranged between the sleeve 2! and that portion of the head it indicated at 28 is a spring 29.

In conditioning the pressure bar l3 for sewing operation by the sewing machine, the nut I5 is adjusted against the spring 26 to compress the spring 29 to bring the pressure foot l4 properly down upon the feed dogs for effectively cooperatin wtin those dogs to effectively feed the goods '15 being sewed upon.

To condition the machine for darning operation, the nut IE is adjusted to permit the upward movement of the pressure bar l3 by the expansion of the spring 28, the degree of expansion being determined by the amount of space desired between the pressure foot l4 and the cloth-feeding dogs. This space should be of that degree which will permit the cloth 25 to be moved freely between the foot i and the feed dogs. In this position of the pressure bar I3 under the control of the spring 29, the sewing machine is now conditioned for darning purposes.

The spring is performs the additional function of yieldably holding the guide finger as from vibrating against a wall of the slot 19 during the operation of the machine. This is accomplished by hearing one end portion 39 of the spring 29 against the finger 2253. After slightly tensioning the spring 29 when mounted upon the pressure bar it, the opposite end portion 3! of the spring is placed to bear against the needle bar bushing I5, I thread 32 or other part of the head ill. The torsional 3 effects of the spring 29 holds the finger against one wall of the slot with suificient yieldable pressure to prevent vibration of the finger and yet not to interfere with the smooth movement of the same in the slot I9.

In thus conditioning the sewing machine for this purpose, it will be apparent that there is required only a simple adjustment of the nut l6.

It will be apparent that the accomplishment of the object requires a minimum alteration in the sewing machine head and the employment of relatively few parts.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claim.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

The combination with a head of a sewing machine in which there is a guide slot, a guide finger movable in the slot, a sleeve provided by the guide 4 finger, a pressure bar arranged in the head and carrying the sleeve, means for connecting the sleeve to the bar, spring elements embracing the bar on opposite sides of the sleeve for resisting the movement of the bar in opposite directions with respect to said head, and means adjustably carried by said head and acting on one of said spring elements to vary the resistance of said spring elements, one of said spring elements having one end portion bearing against said finger and an opposite end portion bearing against an element of said head for yieldably holding said finger against a wall of said slot.

BERNARD A. SCHMITT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

